diff --git a/.azure-pipelines/linux_build.yml b/.azure-pipelines/linux_build.yml
index 2dc092e719..8f13b86d37 100644
--- a/.azure-pipelines/linux_build.yml
+++ b/.azure-pipelines/linux_build.yml
@@ -9,7 +9,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) \
         py-boost=$(boost_version) \
         numpy matplotlib pillow eigen pandas \
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
     conda activate rdkit_build
     conda install -c rdkit nox cairo=1.14.6
   displayName: Setup build environment
diff --git a/.azure-pipelines/linux_build_py37.yml b/.azure-pipelines/linux_build_py37.yml
index 8777b51d4e..fc342d77f0 100644
--- a/.azure-pipelines/linux_build_py37.yml
+++ b/.azure-pipelines/linux_build_py37.yml
@@ -9,7 +9,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) \
         py-boost=$(boost_version) libboost=$(boost_version) \
         numpy matplotlib pillow eigen pandas \
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
     conda activate rdkit_build
     conda install -c rdkit nox cairo=1.14.6
   displayName: Setup build environment
diff --git a/.azure-pipelines/mac_build.yml b/.azure-pipelines/mac_build.yml
index afcd996e68..57e9fa9238 100644
--- a/.azure-pipelines/mac_build.yml
+++ b/.azure-pipelines/mac_build.yml
@@ -21,7 +21,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) \
         py-boost=$(boost_version) libboost=$(boost_version) \
         numpy matplotlib cairo pillow eigen pandas  \
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
   displayName: Setup build environment
 - bash: |
     source ${CONDA}/etc/profile.d/conda.sh
diff --git a/.azure-pipelines/vs_build.yml b/.azure-pipelines/vs_build.yml
index 6c5639d10d..3db71111ae 100644
--- a/.azure-pipelines/vs_build.yml
+++ b/.azure-pipelines/vs_build.yml
@@ -8,7 +8,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) ^
         py-boost=$(boost_version) libboost=$(boost_version) ^
         numpy matplotlib cairo pillow eigen pandas  ^
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
   displayName: Install dependencies
 - script: |
     set Boost_ROOT=
diff --git a/Docs/Book/RDKit_Book.rst b/Docs/Book/RDKit_Book.rst
index 8f8df23663..1a80d14b01 100644
--- a/Docs/Book/RDKit_Book.rst
+++ b/Docs/Book/RDKit_Book.rst
@@ -351,33 +351,33 @@ Please ignore those characters.
 
 **Atoms**
 
-=========  =========================================  ===============  ======  =========
-Primitive                  Property                   "Default value"  Range?    Notes
-=========  =========================================  ===============  ======  =========
-a          "aromatic atom"
-A          "aliphatic atom"
-D          "explicit degree"                          1                Y
-h          "number of implicit hs"                    >0               Y
-H          "total number of Hs"                       1
-r          "size of smallest SSSR ring"               >0               Y
-R          "number of SSSR rings"                     >0               Y
-v          "total valence"                            1                Y
-x          "number of ring bonds"                     >0               Y
-X          "total degree"                             1                Y
-z          "number of heteroatom neighbors"           >0               Y       extension
-Z          "number of aliphatic heteroatom neighbors" >0               Y       extension
+=========  ==========================================  ===============  ======  =========
+Primitive                  Property                    "Default value"  Range?    Notes
+=========  ==========================================  ===============  ======  =========
+a          "aromatic atom" 
+A          "aliphatic atom" 
+D          "explicit degree"                           1                Y
+h          "number of implicit hs"                     >0               Y
+H          "total number of Hs"                        1
+r          "size of smallest SSSR ring"                >0               Y
+R          "number of SSSR rings"                      >0               Y
+v          "total valence"                             1                Y
+x          "number of ring bonds"                      >0               Y
+X          "total degree"                              1                Y
+z          "number of heteroatom neighbors"            >0               Y       extension
+Z          "number of aliphatic heteroatom neighbors"  >0               Y       extension
 \*         "any atom"
-\+         "positive charge"                          1                Y
+\+         "positive charge"                           1                Y
 ++         "+2 charge"
-\-         "negative charge"                          1                Y
+\-         "negative charge"                           1                Y
 \--        "-2 charge"
-^0         "S hybridized"                             n/a              N       extension
-^1         "SP hybridized"                            n/a              N       extension
-^2         "SP2 hybridized"                           n/a              N       extension
-^3         "SP3 hybridized"                           n/a              N       extension
-^4         "SP3D hybridized"                          n/a              N       extension
-^5         "SP3D2 hybridized"                         n/a              N       extension
-=========  =========================================  ===============  ======  =========
+^0         "S hybridized"                              n/a              N       extension
+^1         "SP hybridized"                             n/a              N       extension
+^2         "SP2 hybridized"                            n/a              N       extension
+^3         "SP3 hybridized"                            n/a              N       extension
+^4         "SP3D hybridized"                           n/a              N       extension
+^5         "SP3D2 hybridized"                          n/a              N       extension
+=========  ==========================================  ===============  ======  =========